Blasting device



Aug. 25, 1931. D. HODGE BLASTING DEVICE Filed Jan. v 51. 1929 2 Sheets-Sheet l hm n QN Aug. 25, 1931.

D. HODGE BLASTING DEVICE Filed Jan. 51. 1929 2 Sheets-Sheet 2 @am Nm n www Y NAN N k ,N

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Patented Aug. 25, 1931 UNITED STATES PA'rNr eretici;

DAVID I-IODGE, 0F CENTRALIA,VILLINOIS, ASSIGNOR TO SAFETY MINING COMPANY, OF CHICAGO, ILLINOIS,'A CORPORATION 0F ILLINOIS BLASTING DEVICE Application filed January 31, 1929, Serial No. 336,419, and in Great Britain Uetober 1928.

This invention relates to cartridges, and particularly to cartridges which are discharged by an electric current, requiring a connection to a more or less remote source of current to eEect the discharge, and is Y herein illustrated as applied to a blasting cartridgey of the type disclosed in the copending application of Arthur W. Helmholtz and. Dent Ferrell, Serial'No. 169,441, filed February 19, 1927.

An object of this invention is to provide a cartridge which may be electrically discharged, but which is not subject to being accidentally discharged by accidental or inadvertent contact with current lines or terminals which may be in the neighborhood of the cartridge during storage, transportation or other handling of the cartridge prior to its placement in the drill hole ready for discharge.

Another object of the present invention is to provide a cartridge and a terminal for a current line, which cartridge and line are adapted to be inserted in the drill hole at the site of a blasting operation, the terminal being readily and detachably receivable in the cartridge to establish an electric circuit therefor.

Another object is to provide an electrically operated cartridgeV and current line terminal of the above described type in which the conductors leading toV the electrically discharged element in the cartridge are normally provided with a low resistance shunt connection which prevents the passage of any appreciable current through said element, such as would cause discharge thereof, the parts being so constructed that the current line terminal which may be in the nature of a plug will not only establish the proper electrical connections for the circuit, but will operate to 'disconnect the shunt whereby the cartridge is rendered dischargeable at such times only when the terminal or plug is in inserted position, such as when the cartridge is inserted into the drill hole and con.- nected to lthe plug for discharge.

Another object of the invention is toV provide an improved form of current line cable, plug and cartridge construction by which the present invention may be readily practiced, and which will make for ease and elliciency in operation and simplicity and cheapness in manufacture.

Various other objects not enumerated are contemplated in this invention, which will appear as the description proceeds of the embodiment of the invention herein given for the purpose of illustration.

The present disclosure is given merely by way of example and is-not to be considered as limiting the invention in any regard, but merely as one embodiment thereof, and the scope of the invention will be determinable from an, understanding of the present disclosure as an embodiment of the invention, with recognition of the advantages which the invention produces in the illustrated embodiment.

Referring to theA drawings- Figure 1A is a cross sectional view of one end of a cartridge construction embodying the presentA invention, and Figure 1B is a similar view of the otherend of the cartridge, the entire, cartridge being represented when Figure 1B is placed at the right hand end of Figure 1A. Y v Y v Figure 2 is a cross sectional view of one end of a modified cartridge construction embodying the present invention.

Figure 3 is a view similar to Figure 2 showing a second modified construction embodying the present invention.

Figure 4; is an end elevation of Figure 2 as seen from the left. l

Referring to the drawings, it will be noted that the present invention is disclosed as embodied in a cartridge of the type disclosed v in the cO-pending application above referred to, which comprises a casing of cylindrical construction having a rupturable wall at one end and containing a gaseous medium ink highly compressed form, together with an electrically discharged heating element having the proper connections for establishing a circuit for discharging the cartridge. l

inasmuch as terminals are required, it is desirable to 4provide a higher degree of with grounded electrical circuits it becomes.

obvious that a safety prevention assuring against accidental discharge is highly desir-able, as the possibility of accidental contact of a single terminal with one line of a grounded circuit is not so remote, and suchy contact might result in discharge of the cartridge when the casing, or one conductor thereof, is grounded, as for instance by resting on a metallic car or other grounded conducting part.

rlhe present embodiment of the invention provices a shunt of low resistance, connected across the termina-ls of the heating element so that any accidental passage of current through the cartridge parts will be prevented from acting to discharge the heating element. The cartridge further embodies means for disconnecting the above described shunt and establishing a complete circuit for discharging the heating element at the time the cartridge is connected and inserted in the drill hole for discharge purposes.

Referring to the drawings, it will be noted that the present disclosure of the invention relatesrto a cartridge having a cylinder 10, constricted at one end at 11, with the central opening 12, and having an open end nozzle 13 at its opposite end. For closing the nozzle end a rupturable disk 14 is provided, held by means of the shear ring 15 and the discharge cap or cage 1G, which is screw threaded at 17 to the casing so as to present the rupturable disk in close sealing contact with the knife edge projectionl on the end of the casing. At the opposite end a tube like element 19 is positioned through the opening 12 and insulated therefrom by means of the insulation 20, 21 and 22, which tube serves in the dual capacity of an electrical conductor and an inlet tube for the gaseous medium. Y

The tube is held by means of the flange or collar 23 Vand the nut 24, which are insulated from the casing by means of the insulation 25 and 26, which parts constrict the insulation material and the collar 27 in tight bearingl against the opposite ends of the collar 28, the latter being screw threaded as at 29 in the opening 12 of the casing. Screw threaded on the end of the stem 19, as at 30, and inside of the nut 24, as at 31, is the valve housing 32, having the valve stem 33 screw threaded therein, the valve stem being provided with a needle valve end 34, and key stem 35, all of such construction that the needle valve may be presented in tight sealing relation against the end 36 of the duct 37 provided for the introduction of gas into the cartridge.

'he gas is introduced through the duct 38 in the valve housing by a suitable means clamped tightly thereto, so that 'when the valve is moved away from its seat, gas under pressure may be forced into the cartridge, the construction permitting (upon the introduction of a sufficient amount of gas) the valve to be seated for preventing escape of the gas so introduced prior to the removal of the introducing nozzle, or other means applied against the opening 38.

The above structure is substantially similar to that disclosed in the co-pending application referred to.

The valve stem is provided with suitable packing and glands, represented generally at 39, of the same construction as shown in the co-pending application.

Inside the cartridge,` mounted on the threaded end 40 of the stem 19, is a spring housing 41 containing the spring 42, and forming a slide mounting for the spring pressed contact plate 43. Surrounding the contact plate is a .supporting` tube 44, preferably perforated and terminating short of the opposite end of the cartridge, as shown at 45 in Figure 1B. Positioned in the tube 44 is a heating element 46 of any suitable construction, but which may be of paper tube construction, having plugs 47 at its opposite ends and containing' a suitable material and an electrical conducting wire 48, the latter of which is curled at its opposite ends to bear against the contact plate 43 atone end, and the rupturable disk 14 at its opposite end.

lhe wire passes through the casing and is in association with. the material contained therein so as to render the cartridge dischargeablc upon the 'passage of sufficient current Vthrcugh the con-ducting wire.

lt yfill be noted that one end of the heating' element is in electrical contact with the casing 10 so that the casing will serve as one terminal in establishing the electrical circuit for discharging the cartridge. At the end opposite the discharge end of the cartridge an enclosed casing cap or extension 49 is provided, screw threaded as at 50, and preferably formed of the same diameter as the casing 10, so that the ent-ire unit may be inserted into the drill hole without having projections or other portions thereonwhich will hinder the introduction of the cartridge in the drill holc.

The casing cap 49 is provided with an inner cavity 50 and an opening or socket 51 leading thereinto.

The cavity 50 is lined as at 52 with insulating material to assure against shortcircuiting by contact of any ofthe valve parts previously described, which are heusedwthin the cavity, Bearingagainst the nut 24 is a metallic ring 53,' forming a seat for'the coil spring 54, the outer endl i'n'aintaining a snug fit therefor. The' cap 55, when the cartridge is not connected for discharge, as when inserted in the drill hole, is urgedby the spring 54 in contact with the flange 56, vwhereby the inner end of thesocket opening 51 is closed against the entrance of dirt or moisture into the cavity 50, and further, a low resistanc'eshort-circuiting or shunt connection provided across the terminals of the'heating element preventing accidentaly passage of current therethrough and consequent -discharge thereof prior to the time that the cartridge is actually connected for discharge purposes.

The socket 5l is adapted to receive a plug which vis secured as a permanent connection to the end of a current'line, such as a line of the type leading to and adapted to be used at the site of the blasting operation. The current line may be of any suitable construction, but, for the purpose of this vinvention, is found to serve well when formed of a central conducting core 58, insulated from thecore by Vmeans of the insulating Isleeve GO. The cable or line so formed may, of course, be entirely encased in insulating material 6l. The plug comprises a metallic or conducting member l63, having a flared opening 64 therethrough, lea-ding to the conduit 65 passing therethrough. The conducting portion 63 is provided with lugs GG which cooperate with the slots 67 at the end of the casing cap 49 tofform a breech lock or other suitable quickly acting and readily detachable locking connection. V

The portion 63 is threaded as at 68 for receiving the securing sleeve G9, having .a flanged end at 7 O, VInside of the sleeve 7 O is the conducting element 71, having the female socket portion 72 for receiving the male projection 58 previously described.

zThe conducting element 71 is insulated from the outer casing cap by means of insulation 72 and 73. The inner conducting core 58v of the current line or cable is permanently secured in the' conducting element 7l as at 74, whereas. the core is insulated from the conducting portion 63 bythe insulation 65.

The outer conducting sleeve 59 enters the opening 64 of the conductingV portion 63, and is in electrical contact therewith, as at v75, whereby a plug is provided which may be readily insertedv into the socket for es casing as one terminal ofthe heating element, and the cap 55 as the other terminal of the heating element.

Attention is `directed to the fact that the ,.70 vta-blishing electricall connections with thel plug is of such construction and size that the insulating sleeve 73 contacts the cap 55.

when the plug is completely inserted, and moves 1t away from its short-circuiting con- 'tact with the annular flange 56v of the casing cap. This, it will appear, establishes the complete circuit for discharging the heating element upon the passage of'V current through the two conductors of theV current line.

From the Aforegoing description, it will` be obvious that the inventionprovides a cartridge' which may be readily attached to the current line at the time that the cartridge is inserted in the drill hole for dis-2v charge, and that a high degree of convenience and easeV of manipulation is provided in that various cartridges may be supplied and connected toa common electrical line in succession as they are used, that is to say,

the terminal plug maybe reused with the various cartridges in successive blast-ing operation, the plug'b'elng readily disconnected and reconnected to a new unused cartridge;- This constructlon has proven to be strong? and durable and with the strong breech lock connection it is found that the discharging operation does not damage the plug or its connection with the current line, consequently the spent cartridge may be readily recovered and the pluginserted in a new cartridge ,for a subsequent blasting operation.

In the form shown in Figure 1A it is a feature of the invention to provide the opening 64 for receiving the current line substantially at one margin thereof, or in other words, eccentric to the center, whereby the current line may enter into the vcartridge near the bottom edge thereof so as to permit the current line to rest on the bottom surface ofthe drill hole. This feature is advantageous in assisting in closing the drill hole -behind the cartridge such as bytamping, or with theuse of. dummies or the like, as the current line will be out o'f thev center and always in a given position whereby allowancemay be made therefor,

Referring now to Figure 3, the parts are substantially the same and accordingly will not be described again, except that the current line enters the portionilGS of the Vplug centrally thereof, with the conducting sleeve 159 screwthreaded as at 160 into the 4plug portion, or otherwise securely fixed fao . ure In Figure 3, a modified torni of Dlug is shown which is locked in the end oi the casing cap by means of projections Q66 operatedby balls` 267. 'llhe female conductingelement E271v is VVprovided lwith a screu7 272 for engaging in the end oi: the core conductor of the circuit line. The conducting portion of the plug isinsulated; from the female portionl Aby means ott insulation and 27e. A nut 275 is provided :it the cuter endy to assist in securing the end ci t circuit line to the plug, which nut is seresy t ended the conducting portion 273, as 275. iin enclosed. is provided tor closely engaging the inner end of the circuit line. y

In operation it will be appreciated that .the cartridges as illedand supplied for use will be provided with a shunt of low resistance which will prevent accidental discharge, veven though accidental Contact is made on the inner terminal oi the circuit.v

The ycartridge furtlierprovidcs ygreater assurance against such accidentaldischarge, the inner terminal is the male projection 5i', and is housed Well Within the casing cap Vat asiibsantial distance inwardly ott the edge thereof, and in such protected position that it can only be brought in contact Witlian electrical lineby deliberate insertion or' the line into vthe soclret opening.

rlhe invention also provides a readily detachable connection Which is reuseable ivith the various cartridges in succession, which plug' not only establishes the proper electrical connection for discharging the cartridge, but also disconnects the shunt or short-circuiting connection, which ordinarily maintains the cartridge incapable ot accidental discharge. Y Y

It is obvious that various forms and inodiiications may be made Without departing from the spirit of the present invention, and the present disclosure is not to be considered as limiting the invention in any regard. The scope of the invention is fully set toi-th in the appended claims. i

I claim:

l. In an electrically discharged cartridge, a casing and a heating unit in said casing, said heating unit being electrically connected to said casing and to a terminal Within'said casing, and a detachable means, connected to a source of current, adapted to be inserted in said casing for establishing an electrical circuit 1vith said casing and `terminal, said terminal being normally in electrical contact with said casing, and adapted to be moved out of contact therewith by said detachable means.

2. In a device of the character described,

collar 277' l the combination of an electrically discharged cartridge having vineaiis for receiving a plug for establishing an electrical circuit therefor, a plug for said cartridge and' an electrical conducting line, said line vhaving a core of conducting material and a concentric sheath of conducting material insulated yfrom said core, said plug being mounted lon said line having independent parts insulated rom each other, connected to said core and sheath respectively, said plug being adapted to be inserted and detachably held in said cartridge for establishing an electrical circuit therefor. r

3. In av device oit the character described, an electrical line and a plug having'tvvo terminals secured on the end or" said line, an Velectrically discharged cartridge having two terminals,'and adapted to receive said plug, said terminals being normally in contact, but capable of being moved 'out of contact .by said plug When in inserted position.

Ll. In a device of the character described, the combination of a casing having an opening and a yielding cap; for closing said opening and contacting said casing, an electrically discharged unit in said casing con'- 'nected to said casing and cap respectively,

a plug yconnected to a source of current adapted to be received in said openingand to establish an electrical connection with vsaid casing and cap respectively, said plug uponv movement into connected position serving `to move said cap out of contact With said casing, whereby an velectrical circuit is established for discharging said unit.

5. In a device of the character described, the combination of a casing having an opening and a yielding cap for closing said opening` and contacting said casing, an electrically dischargcd unit in said casing connected to said casing and cap respectively, a plug connected to a source of current adapted to be received in said opening and to establish an electrical connection With said casing and cap respectively, said plug vupon -moveinent into connected position .tov said plug, said line entering said plug substantially at one marginal edge thereof whereby said line may readily rest on the bottom of the drill hole when said cartridge and plug are in inserted position.

7. In a device of the character described,

the' combination ofV a line, andv a plug adapted to be secured iii a cartridge for establishing an electrical connection therewith, said line having concentrically arranged inner and outer conductors, insulated from each other, said plug having two conducting portions insulated :fromA cach other, said line being `secured to saidfplug with the outside conductor in contact with the first of said portion-s, and the inside conductor passing through and insulated from said first portion and beingsecui'ed in contact with the second of said portions.

8. A cartridge of the character described having a casing, andan electrically discharged unit in said casing, a socket in said casing having .terminals for said unit, a plug connected toy a source of current adapted to be received in said socket and having means forfestablishing an electrical connection with said terminals, said socket andV plug having abreech lock connectionl for detacliably` securing? said'plu'g in place; v

9. A cartridge of the character described, comprising a casing, a heating unit in said casing, means connecting said Aheating unit to said casing anda terminal in said casing, an ropening in said casing and a springpressed cap closing said opening and normally maintaining said cap in contact with said casing, a cap spring establishing an electrical connection between said terminal and said cap, aplug connected to a source of current adapted to be received in said opening, having means establishing an electrical connection with said casing and cap respectively, said plug acting to move said cap out of contact with said casing when g said plug is in connected position, whereby an electrical circuit is established for said cartridge, said spring maintaining an electrical connection between said cap and terminal for all positions of said cap.

l0. In an electrically discharged cartridge, a casing having an electrically discharged heating unit contained therein, said casing being connected to serve as one terminal for said heating unit and a second terminal housed within said casing, a socket in said n casing adapted to receive a plug, a plug connected to a source of current adapted to establish a circuit with said terminals, said plug being adapted toY complete the connection by movement into position in said Pi socket, and being capable of slight angular movement for detachably locking said plug against accidental displacement.

11. In an electrically discharged cartridge, a casing and a heating unit in said casing, said heating unit being electrically connected to said casing and to a terminal within said casing and a detachable means connected to a source of current, adapted to be inserted in said casing for establishing an electrical circuit with said casing and terminal, means normally operative to form 4a low resistance shunt between said casing and terminal, said means being rendered inoperative by insertion of said detachable means.

' l2. A-blasting cartridge comprising a casing adapted to receive a charge of liquefied gaslhaving electrically operated means for' vaporizing the charge, the circuit of said means including the casing of'said cartridge cuit,a member detachably associated withl said cartridge vfor conveying current to'said electrodes and means whereby said electro-des areY short circuited when said member is detached from said cartridge.

14. A blasting cartridge having means whereby the same may be electrically racti-r vated and including two electrodes in circuit, a member detachably associated with said cartridge for conveying current to said electrodes and means whereby said electrodes are short circuitedwhen said member is detached' from said cartridge and means associated with said member for ren-v dering said short circuiting means ineifective when said member is attached to said car*-l tridge.

l15. A blasting cartridgev having means whereby-the same may be electrically activated, means i'orv short circuiting said' means, means detachably associated vwith said cartridge for supplying current to the first said means and means whereby said second named means is rendered -ine'ective by the application of said third named means to the cartridge.

16A blasting cartridge having meanswhereby the same may be electrically' acti-r vated, means for short circuiting said means, means detachably associated with said car'- tridge for supplying current to the first said meansv and means vwhereby said second named means is rendered ineffective by the application of said third named means to the cartridge, said secondl named' means beingv normally effective when said third named means is detached from the car;

tridge. Y Y 17 A blasting cartridge comprising a casing adapted to receive a charge of liquelied gas and having electrically activated means for vaporizing said charge, said means consisting of an electric circuit including an electrode insulated from said casing and whereof the said casing constitutes the other electrode and cooperating contact means having electrical connections with the respective electrodes and adapted to be brought into contacting relation for short circuiting said electrodes, means normally urging said contact means into contacting relation to produce and maintain a short circuit, a conductor carrying member detachably associated with said cartridge for supplying current to the circuit including the two said electrodes and means effective upon the attachment of said member to the cartridge for separating said contact means.

18. A blasting cartridge comprising a casing adapted to receive an explosive charge and having electrical means for energizing the charge, said means comprising a circuit including the said casing as one electrode and a second electrode insulated from the casing, a contact member fixed with respect to one of said electrodes and having electrical connection therewith and a second contact movable with respect to but having electrical connection with said other electrede and adapted to engage the first said contact member to provide a short circuit across said electrodes.

Y 19. A blasting cartridge comprising a cas-A ing adapted to receive an explosive charge and having' electrical means for energizing the charge, said means comprising a circuit including the said casing as one electrode and a second electrode insulated from the casing, a contact member fixed with respect to one of said electrodes and having electrical connection therewith and a second Contact movable with respect to but having electrical connection with said other electrode and adapted to' engage the first said contact member to provide a short circuit across said electrodes and spring means for urging said contact members into contacting relation.

20. A blasting cartridge comprising a casing adapted to receive an explosive charge and having electrical means for energizing the charge, said means comprising a circuit including the saidcasing as one electrode and a second electrode insulated from the easing, a contact member fixed with respect to one of said electrodes and having electrical connection therewith and a second contact movable with respect to but having electrical connection with said other electrede and adapted to engage the first said contact member to provide a short circuit across saidelectrodes, means for urging said contact members into contacting relation, a cap for said casing having relatively insulated electrical connections adapted to conduct current to the respective electrodes when attached rto said casing and means whereby the attachment of said cap to said casing causes separation of said contact members.

21. A blasting cartridge comprising a substantially cylindrical metallic body having a gas chamber formed therein and opening at one end thereof, a. pressure responsive discharge device associated with said end, the other end of said body having an open ended cylindrical pocket, a transversevwall separating said gas chamber and pocket, an electrode passing through said wall and insulated therefrom and extending on opposite sides thereof into said pocket and gas chamber respectively, a plug having relatively insulated portions adapted to be connected to the respective leads from a source of electricity, a lug and slot connection be` tween said plug and body and means for electrically connecting a portion of said pluglwith said electrode.

22. An electrically energizable blasting cartridge comprising relatively insulated parts, an electrically energizable device in circuit between said parts, and a detachable plug having lug and slot connection with said cartridge, said plug having relatively insulated portions adapted to make electrical contact with the respective portions of said cartridge, and means associated with said plug for connecting the relatively insulated portions thereofrwith the respective leads from a source of electricity.

Signed at London, England, this fifth day of December, 1928.

DAVID HODGE. 

